Synthetic cholesterylamine-linkers can include derivatives of cholesterol, cholesteryl, or sitosteryl coupled through the linker to an agent for delivery into cells. The cholesterylamines are thought to mimic cholesterol in the capacity and mechanism for enhanced entry into cells. The configuration of the cholesterylamine-linker that is thought to provide for enhanced entry into cells includes a cholesterylamine that is coupled to a linker from the amine, and which linker includes a negative charge at a spatial distance from the amine of the cholesterylamine.
